I use QT since it's early days and the program has been improved ever since with new features.
Jerry and his team are very responsive on questions ( wonder whether they ever sleep ? ).
2 or three years ago, I made the proposal to include Datek's trading window right into QT submitted a few files to Jerry Medved.
He did it within 3 or 4 weeks or so. It was the first brokers you could trade with directly from QT interface
Since then I used QT with several data services, of which stockwatch.com is imho the best bargain for stocktraders
( backfill + realtime data US exchanges for less than 20 USD/month ).
Today, I use it with Interactivebrokers account and it works well.
Jerry just needs to implement the OCA and bracket-orders functionalities and QT is almost complete for my purposes.
I have not yet faced trouble with hardware ressources. ( P4 1.8Mhz, 768MB Ram , ADSL connection ).
Yes, one could need more than one monitor to use all the functions & features at once QT has to offer . However, I'm positiontrading, so the one 19" monitor set at 1280 res is enough for me.
Can only recommend the Software and have the highest regards for QT support.
I'm in no way related to this company and refer only to my own experiences with QT over the last 3 years or so.